CALIFORNIA UNIV LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING
Metals are known to reflect microwaves. For an electromagnetic wave at normal incidence on an ideal conducting surface, there is total reflection of the incident wave, and the electric field E is zero at the surface. In practice, however, no conductor is perfect, i.e. it has a finite conductivity Delta. This imperfectness of the conductor leads to a fraction of the incident energy entering the conductor and dissipating as heat. Therefore, it is possible to exploit the microwave losses in metals for the fabrication of metal-based composites by microwaves. An obvious method is the use of metal powder particles dispersed in a ceramic material. The aim of this paper is to explore some of the parameters involved in the use of metals for the microwave heating of ceramic-metal composites or cermets. Cermets can be of two kinds, oxide- and carbide-based, and can be developed in a wide number of compositions. They combine the useful properties of ceramic and metal materials into one system. In the present work, examples of microwave heating of chromium-alumina and copper-alumina mixtures are presented.
This article is from 'Ceramic Transactions. Volume 21. Proceedings of the Symposium on Microwave Theory and Application in Materials Processing Annual Meeting of the American Ceramic Society (23rd) Held in Cincinnati, Ohio on April 29 - May 3, 1991,' AD-A253 631, p557-563.